This invention relates to a sheet metal connector for anchoring an anchored structural member to an anchoring structural member. The connector works in conjunction with a separate anchor member that is received by or is attached to the anchoring structural member and with fasteners for attaching the connector to the anchored structural member.
Earthquake, hurricanes, tornadoes and floods impose forces on a building that can cause structural failure. To counteract these forces, it has become common practice to strengthen or add ties between the structural members of a building in areas where such cataclysmic forces may be imposed. For example: framed walls can be attached to the foundation rather than merely rest upon it; connections between the framed walls of each floor can be strengthened; and joists can be connected to both their headers and the walls that support the headers. One of the most common connectors designed for this application is called a holdown by the inventor. Holdowns are commonly used to anchor framed walls to the foundation.
Early holdowns were formed from two or more separate pieces of metal welded together. These holdowns had to be painted to prevent rusting. They were heavy and costly to produce.
State of the art holdowns are made from galvanized sheet metal formed on progressive die machines that require no welding or painting. See U.S. Pat. No. 4,665,672 granted May 19, 1987 to Commins, Gilb and Littleton; U.S. Pat. No. 5,092,097 granted Mar. 3, 1992 to Young; U.S. Pat. No. 5,249,404 granted Oct. 5, 1993 to Leek and Commins; and U.S. Pat. No. 6,327,831 granted Dec. 11, 2001 to Leek. These advancements have reduced to cost of making holdowns while increasing their ability to withstand tension forces. However, recent severe earthquakes in San Francisco, Los Angeles and Kobe, Japan demonstrate that holdowns capable of being mass produced and installed inexpensively should be made even stronger for many connections.
Generally, holdown connectors that work in conjunction with a separate anchor member and attach to only one face of the anchored structural member—generally a vertically-disposed stud—work in a common fashion. The anchor member attaches at the seat of the connector. This seat is connected to a pair of side members that are, in turn, connected to a pair of back members. The back members attach to the anchored structural member. Most holdown connectors have side members to increase the strength of the connector or to connect the seat member to the back member.
The connector of the present invention works in a similar fashion to most of the prior art holdowns, such that it is amenable to standard installation practices. The connector of the present invention improves on the prior art by incorporating a number of design features that make it lighter and cheaper to produce while withstanding high tension loads.